Forecasters had feared the storm might develop into a powerful derecho, the term given to storms longer than 240 miles and with winds stronger than 58 mph. A particularly strong derecho ravaged the mid-Atlantic a year ago, killing 22 people.

Whether this storm system ever reached the status of derecho on Wednesday or Thursday may be a formal determination weather experts make later, but the system still unleashed fierce weather.

A western Pennsylvania man died early Thursday in a fire, apparently started by a lightning strike, the state fire marshal told the Associated Press.

A 4-year-old boy was crushed and killed by a poplar tree in a Richmond, Va., park. His father was injured.

A woman, 19, was injured by a lightning strike at a zoo in Rising Sun, Md., and taken to the hospital, the Baltimore Sun reported.

At least one tornado was spotted in Maryland, but dissipated without causing apparent injuries as the storm wound down and began to bear south along the East Coast.

"The heaviest thunderstorms have moved off the mid-Atlantic coast, with just some lingering rain from southern New Jersey through the Delmarva Peninsula," AccuWeather meteorologist Brian Edwards said in a Thursday evening update.

"The biggest concern through the remainder of the evening hours will be locally damaging wind gusts for the eastern third of North Carolina, upstate South Carolina and parts of northern Georgia and northern Alabama," Edwards said.